Klitschko, 34, has suffered a series of injuries since the early 1990s and long before he turned professional. In 1996 he was forced to withdraw from Ukraine's Olympic team and was replaced by his younger brother Wladimir, who won the gold at super heavyweight.
Last year Klitschko admitted in his autobiography that before the Olympic Games he had used steroids to help to repair a damaged knee and it was his knee again which forced him to withdraw from Saturday's World Boxing Council defence against Hasim Rahman in Las Vegas.
Last Saturday Klitschko met two separate experts and postponed this week's fight and on Tuesday he underwent surgery in California, which was successful but meant that he would not be able to fight for another six months. According to the WBC's regulations Klitschko would have been stripped of his title on 10 December, having not fought since 11 December, and after looking at all of his options he decided to quit.
"The decision to retire was difficult but I had no other option because of the injury,'' Klitschko claimed. "I'm pleased to retire at the top and I would like to thank everybody who has supported me.''
Klitschko turned professional in November 1996 and stopped or knocked out his first 27 opponents and managed to win the World Boxing Organisation heavyweight title. However, in April 2000 he lost his WBO title when he was forced to retire in the 10th round against Chris Byrd because of a damaged shoulder.
In 2003 Klitschko was winning on points but starting to tire when he was stopped by Lennox Lewis because he had sustained a series of cuts across his face.
Since that fight with Lewis, Klitschko has suffered many injuries from damaged hands to injured thighs and a bad back which required surgery in April of this year.
Part of the problem is that Klitschko at 6ft 7in and close to 19 stone is clearly finding it far more difficult to prepare for the championship distance of 12 rounds. Once he won the title in April 2004 he was under obligation to make mandatory defences or risk being stripped and with his constant battle against injury his retirement is not really such a great shock.
"I will now have time to lead a normal life and I will get involved in tackling social and socio-political challenges in my native Ukraine,'' Klitschko said.
Earlier this year Don King, the promoter, lobbied the WBC to allow his fighter Rahman to fight Monte Barrett for the WBC's "interim" title. The pair met on 13 August, Rahman won and will in theory now be officially recognised as the WBC's champion.Reuse content